.TH std::ctype::is 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::ctype::is \- std::ctype::is

.SH Synopsis
   Defined in header <locale>
   bool is( mask m, char c ) const;                                      \fB(1)\fP
   const char* is( const char* low, const char* high, mask* vec ) const; \fB(2)\fP

   1) Checks if the character c is classified by the mask m according to the
   classification table returned by the member function table(). Effectively calculates
   table()[(unsigned char)c] & m.
   2) For every character in the character array [low, high), reads its full
   classification mask from the classification table returned by the member function
   table() (that is, evaluates table()[(unsigned char)*p] and stores it in the
   corresponding element of the array pointed to by vec.

   If (unsigned char)c >= std::ctype<char>::table_size, then an implementation-defined
   value is substituted instead of table()[(unsigned char)c], possibly different for
   different values of c.

.SH Parameters

   c    - character to classify
   m    - mask to use for classifying a single character
   low  - pointer to the first character in an array of characters to classify
   high - one past the end pointer for the array of characters to classify
   vec  - pointer to the first element of the array of masks to fill

.SH Return value

   1) true if c is classified by m in table(), false otherwise.
   2) high

.SH Notes

   Unlike the primary template std::ctype, this specialization does not perform a
   virtual function call when classifying characters. To customize the behavior, a
   derived class may provide a non-default classification table to the base class
   constructor.

.SH Example

    This section is incomplete
    Reason: no example

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

     DR   Applied to               Behavior as published               Correct behavior
                     overload (2) copied the values from vec into
   LWG 28 C++98      table(),                                          corrected
                     which is the reverse of the intended behavior

.SH See also

   do_is     classifies a character or a character sequence
   \fB[virtual]\fP \fI(virtual protected member function of std::ctype<CharT>)\fP

.SH Category:
     * Todo no example
